An iron crawler has been much used for an endless track running gear, which is used for running parts of the construction machine etc. However, recently a rubber crawler has been preferably used not to damage a pavement. FIG. 101 is a plan view showing an example of a conventional rubber crawler. FIG. 102 is an Xxe2x80x94X line sectional view in FIG. 101, and FIG. 103 is a Yxe2x80x94Y line sectional view in FIG. 101. In the figures, 67 is a core guide protrusion, 64 is a core, 65 is a rubber elastic body, and 66 is an extensible reinforcing layer.
Recently, since the construction machine using the rubber crawler is comfortable to drive and is little fatiguing a driver, it has been more often used under severe conditions except the pavement etc.
Therefore, the construction machine often runs over sharp rocks and scrap wood in civil engineering works. In an operating condition, a foreign substance is caught between the rubber crawler and a driving wheel or an idler wheel, thereby generating unusual tension on the rubber crawler. Therefore, a steel cord of the extensible reinforcing layer is cut, or a steel cord wrapping part is pulled out.
Catching the foreign substance as above-mentioned, or inverse warping of the rubber crawler during running on rough terrain, causes the core guide protrusion to be caught on a chassis. Since the cord adds mighty driving force from the driving wheel, the catching phenomenon destroys adhesion between the core and the steel cord. Owing to this, the core protrudes.
Moreover, during running on rough terrain, a cut crack occurs in a rubber part. In this case, when the crack reaches the steel cord of the extensible reinforcing layer of the rubber crawler, the steel cord is severed due to a cut or corrosion, thereby making the machine unusable as a rubber crawler, though the rubber part can be still used.
In order to solve the above-mentioned problems, this invention aims to provide a rubber crawler to be usable under severe operating conditions.
The present invention relates to a rubber crawler comprising a core consisting of generally parallelepiped blocks each having two longitudinally spaced through holes in the lower surface region and bars inserted in the through holes. The generally parallelepiped blocks are arranged in two series, with the blocks of one of the series laterally overlapping the blocks of the other series, and with sprocket engaging holes disposed therebetween, and the bars are inserted in alternately corresponding through holes in adjacent generally parallelepiped blocks. The bars are connected within the generally parallelepiped blocks and embedded in the rubber crawler.
Besides, the above-mentioned problems can be solved by means of choosing and combining the following listing compositions suitably.
1. At least, a minimum rubber crawler unit is formed from two generally parallelepiped blocks and one bar to insert into the through hole. Then, a rubber crawler unit comprising of plural generally parallelepiped blocks and plural bars is formed from the minimum rubber crawler unit. The generally parallelepiped blocks are arranged in two series, with the blocks of one of the series laterally overlapping the blocks of the other series, and with sprocket engaging holes disposed therebetween, and the bars are inserted in alternately corresponding through holes in adjacent generally parallelepiped blocks. The bars are connected within the generally parallelepiped blocks and embedded in the rubber crawler unit.
The generally parallelepiped blocks are provided at both ends of the rubber crawler unit in a crawler circumferential direction, and at one side of right and left of the rubber crawler unit in a crawler width direction with the engaging holes disposed therebetween. Connecting bars are inserted in connecting generally parallelepiped block through holes and connecting bar insertion holes of the generally parallelepiped blocks, respectively, thereby connecting adjacent rubber crawler units in the crawler circumferential direction at their ends. Thus, an endless rubber crawler can be formed.
2. The bar is a stick member having a circular section, and a bush is fitted in a sprocket engaging part of the bar.
3. A diameter of the through hole of the generally parallelepiped block is larger than the outer diameter of the bar. Filling a gap between the through hole and the bar with rubber, the bar can be connected through the rubber of an elastic material.
4. The through hole of the generally parallelepiped block is formed into different sizes in its front face and back face, one side small and the other side large. Besides, a bar shake stop protrusion is provided within the through hole.
5. An upper surface region of the generally parallelepiped block protrudes out of an inner circumference side of the rubber crawler. In this case, the protrusion may be formed in a horn shape, or its top part may be formed flat so as to serve as a travelling rolling surface which a rolling wheel contacts.
6. A wing part is provided on an outside of the generally parallelepiped block in the crawler width direction. In this case, the wing part is formed so as to be located between the bar and the bar, or so as to extend in the crawler circumferential direction.
7. Lateral shift control parts are provided to both ends of the generally parallelepiped block in its length direction. When embedded in the rubber crawler, the lateral shift control parts may be overlapped with those of an adjoining generally parallelepiped block in view of the crawler circumferential direction, respectively.
8. In order to reinforce the rubber crawler, a reinforcing layer is embedded in the rubber crawler in all its circumference, the reinforcing layer distributed on both sides in the crawler width direction. Here, the reinforcing layer may be embedded in both sides of the bar, the outer circumference side and the inner circumference side, or in either one of them. Besides, the reinforcing layer may be made to meander on inclining towards a center of the thickness of the rubber crawler between the bar and the bar, or in the inner circumference side and the outer circumference side alternately between two bars. In this case, a connecting ring and a generally parallelepiped auxiliary block may be arranged on the outside of the generally parallelepiped blocks, shifted by half a pitch relative thereto. Moreover, the reinforcing layer may be embedded on the outside of the connecting ring (tread side).
9. In the above-mentioned case, a lug is provided so as to shift by half a pitch to the connecting ring.
10. A top face of the generally parallelepiped auxiliary block in the inner circumference side of the rubber crawler is exposed, or covered with rubber to a degree of burr.
11. A pipe is fitted on the bar of the outside of the generally parallelepiped block. Besides, the outside part of the generally parallelepiped block may be attached and detached. Here, an inner wall of the pipe may be covered with a high molecular compound layer, such as rubber.
12. A band provided to the outside part of the generally parallelepiped block is divided into one to plural single substances or owner end bands, which have two or more bars. In this case, adjoining portions of ends of the divided single substance or the owner end band may touch face to face each other.
13. The end of the simple substance or the owner end band is located on a circle centering on the center of the bar in a right-angled section of the bar length direction.
Due to the present invention, the cores consisting of the bars and the generally parallelepiped blocks are connected endlessly. Here, the generally parallelepiped blocks having two through holes are arranged in two series, with the blocks of one of the series laterally overlapping the blocks of the other series, and with the engaging holes disposed therebetween, and the bars are inserted in these through holes one by one to connect the cores. Therefore, even if any deep external injury is inflicted on the rubber crawler, it does not fracture like the conventional rubber crawler. Besides, even if the generally parallelepiped block is caught in the chassis of the machine, the core never protrudes unexpectedly.
The bar is a stick member, and its section form is made circular or polygonal in accordance with a purpose for use. However, the form is not limited to these. Besides, the bar may be either full or hollow. When the bar is full, it has the highest intensity. When the bar is hollow, it is lightweight.
Moreover, when the section form is circular, the intensity is the highest. However, the Other forms can be selected freely.
Furthermore, when fitting the bush in the sprocket engaging part of the bar, a different size sprocket can be applied by changing the size of the bush. When using a wear resistant bush, the rubber crawler improves its durability, thereby serving as a long-lived one. In this case, the bush can be formed integrally with the generally parallelepiped block.
Besides, the bar may be formed into a flat plate having fixed thickness except a portion in which the generally parallelepiped block is fitted. In addition, the bar may be formed in the shape of a ladle as one end on the bar length direction is broader than a diameter of the central part.
The diameter of the through hole of the generally parallelepiped block is larger than that of the bar, and the gap therebetween is filled with rubber to be pasted up. Here, the bar is fixed through the rubber of an elastic material. Even if a high load is applied to the rubber crawler, the rubber crawler can elongate somewhat. In contrast to an iron ring, unusual tension is hardly generated, and the crawler is prevented from breaking easily. Though the bar is fixed to the through hole of the generally parallelepiped block through the elastic material, it is fixed firmly in comparison with the conventional rubber crawler. Therefore, the rubber crawler is prevented rocking and derailing broadly, and lessens rock and oscillations of each bar.
The rubber crawler moves through a rubber layer between the bar and the through hole of the generally parallelepiped block, thereby preventing friction between the through hole and the bar, preventing its abrasion, and preventing creaking sound.
The through hole of the generally parallelepiped block is made with its sprocket engaging hole side large and the other side small. In this case, the bar shake stop protrusion is provided to the inner wall of the enlarged through hole, the rubber crawler decreases twists and shake of the bar.
In this case, in FIG. 74A, a bar wing having a breadth larger than a through hole-through hole interval between adjacent generally parallelepiped blocks as shown is provided to one side of the bar, which corresponds to the outside portion of the generally parallelepiped block in the crawler width direction. A bar wing through hole, which the bar is inserted in its portion equivalent to the through hole of the adjoining generally parallelepiped block is provided to the bar wing. As shown in FIG. 75, when inserting the bar, which is inserted in the through hole of the adjoining generally parallelepiped block, into the bar wing through hole similarly, the rubber crawler is connected with the generally parallelepiped block and the bar wing. Accordingly, it is connected still more firmly.
In the present invention, the rubber crawler is not limited to an integral endless composition. That is the endless rubber crawler can be formed as follows. At least, a minimum rubber crawler unit consisting of two generally parallelepiped blocks and one bar to be inserted into their through holes. The generally parallelepiped blocks are arranged in a zigzag pattern with sprocket engaging holes disposed therebetween, and the bars are inserted in alternately corresponding through holes in adjacent generally parallelepiped, blocks. The bars are connected with the generally parallelepiped blocks, and embedded in the rubber crawler unit. The generally parallelepiped blocks are provided to both ends of the rubber crawler unit in the crawler circumferential direction, which are either right or left side in the crawler width direction with the engaging hole disposed therebetween. The bar is inserted into the connecting generally parallelepiped block through, hole of the generally parallelepiped block at the end of the rubber crawler unit and at the end of the adjoining rubber crawler unit in the crawler circumferential direction, and is connected with them. (When the generally parallelepiped block of the one end is left-hand side, the generally parallelepiped block of the end of the adjoining rubber crawler unit is arranged at right-hand side.) In this way, an endless rubber crawler may be formed.
In this case, the rubber crawler unit is made up of plural generally parallelepiped blocks and plural bars besides the minimum rubber crawler unit consisting of two generally parallelepiped blocks and one bar inserted into their through holes, and forms a rubber crawler unit having necessary length. Here, the rubber crawler may be made endless by connecting same kind of rubber crawler unit, or different kind of rubber crawler unit with suitably combined, or both ends of one rubber crawler unit.
Accordingly, if the rubber crawler should be damaged partially, only the damaged portion needs to be exchanged. Therefore, compared with exchanging the whole rubber crawler, cost is reduced, waste decreases, and abandonment processing also becomes easy.
When the protrusion of the generally parallelepiped block in the inner circumference side of the rubber crawler (anti-tread side) is protruded in the shape of a horn, it serves as a slip-preventing guide of the rolling wheel or the idler wheel. Besides, when the top of the protrusion is formed flat, it serves as a rolling contact surface that the rolling wheel contacts with, thereby serving as a rubber crawler interchangeable with an iron crawler.
Besides, the wing part provided to the generally parallelepiped block serves as a rolling part of an outer rolling wheel, and decreases oscillations when the outer rolling wheel travels on the rubber crawler. When the wing part is extended in the rubber crawler circumferential direction, this effect is increased. Moreover, when the wing part is provided between the bar and the bar, the generally parallelepiped block becomes cheap as well as has the above effect, thereby reducing cost.
When providing the lateral shift control part to the both ends of the generally parallelepiped block in its length direction and embedding in the rubber crawler, if each lateral shift control part of adjacent generally parallelepiped blocks is overlapped in view of the rubber crawler circumferential direction, a lateral shift is prevented. Therefore, the rubber crawler is prevented a derailment.
Besides, when forming one end of the lateral shift control part convex and the other end concave, and overlapping these in the shape of a nest, the lateral shift and twists are prevented. Therefore, the rubber crawler is prevented the derailment more.
When embedding the reinforcing layer into the inner or the outer circumference of the bar, driving force brought from the sprocket to the bar is distributed on the whole rubber crawler through the reinforcing layer, and transmitted to the lug efficiently, thereby providing sufficient traction. Simultaneously, partial stress around the bar is also eased, thereby improving durability of the rubber crawler.
The reinforcing layer is suitably chosen from Vinylon, Nylon, Tetron, Kevlar, and steel cord etc. Here, each material of the reinforcing layers in the outer circumference side and the inner circumference side may be either same or different. Besides, its form may be either linear or textile, and is not limited to these.
Besides, the reinforcing layer can be provided to either the inner circumference side or the outer circumference side.
Next, connecting rings as shown in FIGS. 45 to 48 are arranged in a zigzag pattern on the outside, in the crawler width direction, the rings shifted by half a pitch to the generally parallelepiped block. Two adjacent bars are inserted with shifting by half a pitch thereto as shown in FIG. 44 and all bars are connected at both sides of the sprocket engaging hole. In this case, when the crawler coils around the driving wheel or the idler wheel, or when tension added on the crawler changes, distortion repeatedly generated to rubber between the generally parallelepiped blocks is reduced, thereby preventing rubber fatigue destruction therebetween. Besides, the rubber crawler lessens oscillations and twists, thereby preventing its derailment.
Moreover, the connecting ring increases rigidity of the rubber part and distributes the driving force brought from the sprocket on the whole rubber crawler to transmit to the lug, thereby providing sufficient traction. In this case, when the above-mentioned reinforcing layer is embedded to the outer circumference side of the connecting ring (tread side), the driving force is distributed more uniformly, thereby providing still more sufficient traction.
The connecting ring having each form such as FIG. 45, FIG. 46 and FIG. 48 is made of spring steel, steel cords, high intensity fibers etc. When the connecting ring in FIG. 47 is made of the high intensity fibers, it has spring nature, thereby preventing unusual tension. Accordingly, the rubber crawler is hardly fractured.
In this case, in the rubber crawler provided with the connecting ring, when the lug is arranged with shifting by half a pitch to the connecting ring (one pitch to the bar) in the crawler circumferential direction, rigidity between the connecting rings is prevented falling. The rigidity is balanced as a whole. Accordingly, the traction from the sprocket is efficiently transmitted to the lug.
In the above-mentioned rubber crawler, the connecting ring may be used as the generally parallelepiped auxiliary block. In this case, the diameter of the through hole provided to the generally parallelepiped auxiliary block is larger than the outer diameter of the bar, and rubber is filled into the gap between the through hole and the bar to be pasted up. Here, the bar is fixed through the rubber of an elastic material. Therefore, the rubber crawler is provided with more or less elongation and spring nature, thereby hardly generating unusual tension. Besides, since the bar is fixed firmly, the rubber crawler lessens oscillations and hardly derails.
When exposing the top face of the generally parallelepiped auxiliary block in the inner circumference side of the rubber crawler, or when covering it with a thin rubber layer to a degree of burr, it serves as a rolling contact surface that a rolling wheel of an outer rolling wheel type travels on.
When the pipe is fitted to the bar outside the generally parallelepiped block in the crawler width direction, the rubber part wrapping the pipe can be attached or detached easily. When the rubber part is damaged, only it can be exchanged, thereby serving as an economical rubber crawler so that only the rubber crawler to be damaged at an early stage can be independently molded.
The inner wall of the pipe is covered with a thin high molecular compound layer such as rubber, epoxy, urea, urethane, and liquefied rubber, thereby preventing noises due to friction between the pipe and the bar, and enabling stable adhesion to the bar.
Furthermore, when the band provided to the outside part of the generally parallelepiped block in the crawler width direction is divided into one to plural simple substances or owner end bands having two or more bars, the damaged rubber part is exchanged easily. In this case, the band is divided at one position or plural positions freely, and may be divided into the simple substances having two bars.
In addition, in the rubber crawler provided with the connecting ring, when dividing the rubber crawler per connecting ring (the simple substance having two bars), the divided simple substance becomes small, thereby being produced with a small molding apparatus. Besides, it is easy to convey and exchange.
On the other hand, when touching face to face the ends of the divided simple substance or owner end band in the crawler circumferential direction, each gap therebetween disappears, thereby preventing mud and foreign substances going up at the inner circumference side of the rubber crawler. As well as prevented the derailment and unusual tension due to the foreign substances bit between the sprocket and the rubber crawler, the rubber crawler is prevented sinking and decreasing its revolving nature at a soft ground.
When touching face to face the ends of the divided simple substance or the owner end band in the crawler circumferential direction, if a circle of each end is located on a circle centering on the bar axial center in view of a right-angled section in the bar length direction, the ends can keep the touching. In this case, when the rubber crawler coils to an idler or a sprocket or drives on rough road surface, it is transformed into the inner or the outer circumference side, and the touching position of the end moves. Even in thus state, mud and foreign substances are prevented coming in the inner circumference side of the rubber crawler, thereby preventing the unusual tension and the danger of the derailment.